Augmenting the client with Vue.js

Nicolas Fränkel - Sep 26 - - Dev Community

In my previous post, I laid the ground to build upon; now is the time to start "for real".

I heard a lot of Vue.js. Additionally, a friend who transitioned from developer to manager told me good things about Vue, which further piqued my interest. I decided to have a look at it: it will be the first "lightweight" JavaScript framework I'll study - from the point of view of a newbie, which I am.

Laying out the work

I explained WebJars and Thymeleaf in the last post. Here's the setup, server- and client-side.

Server-side

Here is how I integrate both in the POM:

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>       <!--1-->
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId> <!--2-->
    </dependency>
    <dependency>
        <groupId>org.webjars</groupId>
        <artifactId>webjars-locator</artifactId>               <!--3-->
        <version>0.52</version>
    </dependency>
    <dependency>
        <groupId>org.webjars.npm</groupId>
        <artifactId>vue</artifactId>                           <!--4-->
        <version>3.4.34</version>
    </dependency>
</dependencies>
Enter fullscreen mode Exit fullscreen mode
  1. Spring Boot itself; I decided on the regular, non-reactive approach
  2. Spring Boot Thymeleaf integration
  3. WebJars locator, to avoid specifying the Vue version on the client-side
  4. Vue, finally!

I'm using the Kotlin Router and Bean DSLs on the Spring Boot side:

fun vue(todos: List<Todo>) = router {                                    //1
    GET("/vue") {
        ok().render("vue", mapOf("title" to "Vue.js", "todos" to todos)) //2-3
    }
}
Enter fullscreen mode Exit fullscreen mode
  1. Pass a static list of Todo objects
  2. See below
  3. Pass the model to Thymeleaf

If you're used to developing APIs, you're familiar with the body() function; it returns the payload directly, probably in JSON format. The render() passes the flow to the view technology, in this case, Thymeleaf. It accepts two parameters:

  1. The view's name. By default, the path is /templates and the prefix is .html; in this case, Thymeleaf expects a view at /templates/vue.html
  2. A model map of key-value pairs

Client-side

Here's the code on the HTML side:

<script th:src="@{/webjars/axios/dist/axios.js}" src="https://cdn.jsdelivr.net/npm/axios@1.7/dist/axios.min.js"></script> <!--1-->
<script th:src="@{/webjars/vue/dist/vue.global.js}" src="https://cdn.jsdelivr.net/npm/vue@3/dist/vue.global.js"></script> <!--2-->
<script th:src="@{/vue.js}" src="../static/vue.js"></script>             <!--3-->
<script th:inline="javascript">
/*<![CDATA[*/
    window.vueData = {                                                   <!--4-->
        title: /*[[${ title }]]*/ 'A Title',
        todos: /*[[${ todos }]]*/ [{ 'id': 1, 'label': 'Take out the trash', 'completed': false }]
    };
/*]]>*/
</script>
Enter fullscreen mode Exit fullscreen mode
  1. Axios helps making HTTP requests
  2. Vue itself
  3. Our client-side code
  4. Set the data

As explained in last week's article, one of Thymeleaf's benefits is that it allows both static file rendering and server-side rendering. To make the magic work, I specify a client-side path, i.e., src, and a server-side path, i.e., th:src.

Static view of the HTML page with Vue.js

The Vue code

Now, let's dive into the Vue code.
We want to implement several features:

  1. After the page load, the page should display all Todo items
  2. When clicking on a Todo completed checkbox, it should set/unset the completed attribute
  3. When clicking on the Cleanup button, it deletes all completed Todo
  4. When clicking on the Add button, it should add a Todo to the list of Todo with the following values:
    • id: Server-side computed ID as the max of all other IDs plus 1
    • label: value of the Label field for label
    • completed: set to false

Our first steps into Vue

The first step is to bootstrap the framework. We have already set up the reference for our custom vue.js file above.

document.addEventListener('DOMContentLoaded', () => {                    //1
  // The next JavaScript code snippets will be inside the block
}
Enter fullscreen mode Exit fullscreen mode
  1. Run the block when the DOM has finished loading

The next step is to let Vue manage part of the page. On the HTML side, we must decide which top-level part Vue manages. We can choose an arbitrary <div> and change it later if need be.

<div id="app">
</div>
Enter fullscreen mode Exit fullscreen mode

On the JavaScript side, we create an app, passing the CSS selector of the previous HTML <div>.

Vue.createApp({}).mount('#app');
Enter fullscreen mode Exit fullscreen mode

At this point, we launch Vue when the page loads, but nothing visible happens.

The next step is to create a Vue template. A Vue template is a regular HTML <template> managed by Vue. You can define Vue in Javascript, but I prefer to do it on the HTML page.

Let's start with a root template that can display the title.

<template id="todos-app">                                                <!--1-->
  <h1>{{ title }}</h1>                                                   <!--2-->
</template>
Enter fullscreen mode Exit fullscreen mode
  1. Set the ID for easy binding
  2. Use the title property; it remains to be set up

On the JavaScript side, we must create the managing code.

const TodosApp = {
    props: ['title'],                                                    //1
    template: document.getElementById('todos-app').innerHTML,
}
Enter fullscreen mode Exit fullscreen mode
  1. Declare the title property, the one used in the HTML template

Finally, we must pass this object when we create the app:

Vue.createApp({
    components: { TodosApp },                                            //1
    render() {                                                           //2
        return Vue.h(TodosApp, {                                         //3
            title: window.vueData.title,                                 //4
        })
    }
}).mount('#app');
Enter fullscreen mode Exit fullscreen mode
  1. Configure the component
  2. Vue expects the render() function
  3. h() for hyperscript creates a virtual node out of the object and its properties
  4. Initialize the title property with the value generated server-side

At this point, Vue displays the title.

Basic interactions

At this point, we can implement the action when the user clicks on a checkbox: it needs to be updated in the server-side state.

First, I added a new nested Vue template for the table that displays the Todo. To avoid lengthening the post, I'll avoid describing it in detail. If you're interested, have a look at the source code.

Here's the starting line template's code, respectively JavaScript and HTML:

const TodoLine = {
    props: ['todo'],
    template: document.getElementById('todo-line').innerHTML
}
Enter fullscreen mode Exit fullscreen mode 
<template id="todo-line">
    <tr>
        <td>{{ todo.id }}</td>                                           <!--1-->
        <td>{{ todo.label }}</td>                                        <!--2-->
        <td>
            <label>
                <input type="checkbox" :checked="todo.completed" />
            </label>
        </td>
    </tr>
</template>
Enter fullscreen mode Exit fullscreen mode
  1. Display the Todo id
  2. Display the Todo label
  3. Check the box if its completed attribute is true

Vue allows event handling via the @ syntax.

<input type="checkbox" :checked="todo.completed" @click="check" />
Enter fullscreen mode Exit fullscreen mode

Vue calls the template's check() function when the user clicks on the line. We define this function in a setup() parameter:

const TodoLine = {
    props: ['todo'],
    template: document.getElementById('todo-line').innerHTML,
    setup(props) {                                                                 //1
        const check = function (event) {                                           //2
            const { todo } = props
            axios.patch(                                                           //3
                `/api/todo/${todo.id}`,                                            //4
                { checked: event.target.checked }                                  //5
            )
        }
        return { check }                                                           //6
    }
}
Enter fullscreen mode Exit fullscreen mode
  1. Accept the props array, so we can later access it
  2. Vue passes the event that triggered the call
  3. Axios is a JavaScript lib that simplifies HTTP calls
  4. The server-side must provide an API; it's outside the scope of this post, but feel free to check the source code.
  5. JSON payload
  6. We return all defined functions to make them accessible from HTML

Client-side model

In the previous section, I made two mistakes:

  • I didn't manage any local model
  • I didn't use the HTTP response's call method

We will do that by implementing the next feature, which is the cleanup of completed tasks.

We now know how to handle events via Vue:

<button class="btn btn-warning" @click="cleanup">Cleanup</button>
Enter fullscreen mode Exit fullscreen mode

On the TodosApp object, we add a function of the same name:

const TodosApp = {
    props: ['title', 'todos'],
    components: { TodoLine },
    template: document.getElementById('todos-app').innerHTML,
    setup() {
        const cleanup = function() {                                               //1
            axios.delete('/api/todo:cleanup').then(response => {                   //1
                state.value.todos = response.data                                  //2-3
            })
        }
        return { cleanup }                                                         //1
    }
}
Enter fullscreen mode Exit fullscreen mode
  1. As above
  2. Axios offers automated JSON conversion of the HTTP call
  3. state is where we store the model

In Vue's semantics, the Vue model is a wrapper around data that we want to be reactive. Reactive means two-way binding between the view and the model. We can make an existing value reactive by passing it to the ref() method:

In Composition API, the recommended way to declare reactive state is using the ref() function.

ref() takes the argument and returns it wrapped within a ref object with a .value property.

To access refs in a component's template, declare and return them from a component's setup() function.

-- Declaring Reactive State

Let's do it:

const state = ref({
    title: window.vueData.title,                                         //1-2
    todos: window.vueData.todos,                                         //1
})

createApp({
    components: { TodosApp },
    setup() {
        return { ...state.value }                                        //3-4
    },
    render() {
        return h(TodosApp, {
            todos: state.value.todos,                                    //5
            title: state.value.title,                                    //5
        })
    }
}).mount('#app');
Enter fullscreen mode Exit fullscreen mode
  1. Get the data set in the HTML page, via Thymeleaf, as explained above
  2. We change the way we set the title. It's not necessary since there's no two-way binding - we don't update the title client-side, but I prefer to keep the handling coherent across all values
  3. Return the refs, as per Vue's expectations
  4. Look, ma, I'm using the JavaScript spread operator
  5. Configure the object's attributed from the state

At this point, we have a reactive client-side model.

On the HTML side, we use the relevant Vue attributes:

<tbody>
    <tr is="vue:todo-line" v-for="todo in todos" :key="todo.id" :todo="todo"></tr> <!--1-2-->
</tbody>
Enter fullscreen mode Exit fullscreen mode
  1. Loop over the list of Todo objects
  2. The is attribute is crucial to cope with the way the browser parses HTML. See Vue documentation for more details

I've described the corresponding template above.

Updating the model

We can now implement a new feature: add a new Todo from the client. When clicking on the Add button, we read the Label field value, send the data to the API, and refresh the model with the response.

Here's the updated code:

const TodosApp = {
    props: ['title', 'todos'],
    components: { TodoLine },
    template: document.getElementById('todos-app').innerHTML,
    setup() {
        const label = ref('')                                            //1
        const create = function() {                                      //2
            axios.post('/api/todo', { label: label.value }).then(response => {
                state.value.todos.push(response.data)                    //3
            }).then(() => {
                label.value = ''                                         //4
            })
        }
        const cleanup = function() {
            axios.delete('/api/todo:cleanup').then(response => {
                state.value.todos = response.data                        //5
            })
        }
        return { label, create, cleanup }
    }
}
Enter fullscreen mode Exit fullscreen mode
  1. Create a reactive wrapper around the title whose scope is limited to the function
  2. The create() function proper
  3. Append the new JSON object returned by the API call to the list of Todo
  4. Reset the field's value
  5. Replace the whole list when deleting; the mechanism is the same

On the HTML side, we add a button and bind to the create() function. Likewise, we add the Label field and bind it to the model.

<form>
    <div class="form-group row">
        <label for="new-todo-label" class="col-auto col-form-label">New task</label>
        <div class="col-10">
            <input type="text" id="new-todo-label" placeholder="Label" class="form-control" v-model="label" /> <!--1-2-->
        </div>
        <div class="col-auto">
            <button type="button" class="btn btn-success" @click="create">Add</button> <!--3-->
        </div>
    </div>
</form>
Enter fullscreen mode Exit fullscreen mode

Vue binds the create() function to the HTML button. It does call it asynchronously and refreshes the reactive Todo list with the new item returned by the call. We do the same for the Cleanup button, to remove checked Todo objects.

Note that I didn't intentionally implement any error-handling code to avoid making the code more complex than necessary. I'll stop here as we gained enough insights for a first experience.

Conclusion

In this post, I took my first steps in augmenting an SSR app with Vue. It was pretty straightforward. The biggest issue I encountered was for Vue to replace the line template: I didn't read the documentation extensively and missed the is attribute.

However, I had to write quite a few lines of JavaScript, though I used Axios to help me with HTTP calls and didn't manage errors.

In the next post, I'll implement the same features with Alpine.js.

The complete source code for this post can be found on GitHub:

GitHub logo ajavageek / compare-frontends

Demo code for the series on AJAX and SSR

Go further:

Originally published at A Java Geek on September 22nd, 2024

Image
How Do AI-Based Interview Chatbots Improve Recruitment Efficiency?

ai, chatbot
Image
Agen Judi Online yang Punya Layanan Peserta Terhebat
Image
Key Differences in Static vs Rotating Proxies

staticproxy, rotatingproxy
Image
MtTreeView

react, webdev, javascript, programming
Image
Boost Your Grades: Expert Assignment Help Services in Adelaide Explained
Image
10 Websites To Help You To Become A Proficient In Compensation For Asbestos
Image
Tips for Building a Successful Alibaba Scraper

alibabascraper, rotatingproxy
Image
Cómo usar varias SSH keys para diferentes repositorios de GitHub (o GitLab)

git, github, setup, tutorial
Image
Accelerating SaaS MVP Development: A Guide to Fast-Tracking Your Web App

softwaredevelopment, mvp, saas, fullstackdevelopment
Image
Bezawada Hospitals – Leading Orthopedic and Multispecialty Hospital in Vijayawada for Quality Healthcare Services

orthopedic, orthopedician
Image
Vashikaran Specialist Bangali Babaji +91-9660722449 Genuine Black Magic In Kadapa

webdev, gh
Image
<h1>Dakkapel Amersfoort</h1>
Image
Why Every Medical Practice Needs a Skilled Patient Receptionist
Image
How to Find a Free AI Video Generator

ai, api, video, ads
Image
LMCHING Launches Innovative Trade-in Program to Foster Sustainability and Customer Loyalty
Image
keringanan bermain dalam web slots online terhebat
Image
Emerging Trends in DeFi: How to Stay Ahead as an Entrepreneur

development
Image
Top Tips for Memorable Car Travels in Bhubaneswar: Best Routes, Sights & More

car, rental, bhubaneswar
Image
Chronos Quantum-Powered AI
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .